Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 DOI: 10.24411/2619-0761-2020-10013 УДК 351.02 A GEOLOGICAL OVERVIEW OF DIGITALIZED ROCK DRILL CORE SAMPLES OF ORDOVICIAN PERIOD IN Шоммет Ю.*, Эйнасто Р. Таллинская техническая высшая школа, г. Таллин, Эстония J. Šommet*, R. Einasto TTK University of Applied Sciences, Tallin, Estonian *E–mail: [email protected] Abstract. The aim of this paper is to give a proper overview of scanning methodology, scanned drill core samples, demonstrate sedimentary rock samples as a perfect geological material for digital scanning methodology, which helps to archive important geological information, to select necessary texture and structure designs of rock materials, and to follow its peculiarities. The scanning method- ology is a perfect tool for observing and assessing all rock samples for new investigations or layer- to-layer mining planning and selecting the best mining-geological conditions and even pattern selection for decorations in architectural works. The described and used methodology is available and free for everyone: researchers, mining engineers or mining development companies as well as geologists and others. Carbonate rocks are mined worldwide but only in Estonia, one of them – limestone - is a national stone, thus mainly scanned limestone samples were used in this research. As a result, all drill core rock layers are accurately identified and the most important of them are described in detailed laboratory study. The findings are highly relevant for local and regional stratigraphy and represent the Ordovician Period in Baltic States. Keywords: Scanning methodology, oil shale, limestone, dolostone, geological information, data digitalization. Introduction. present in Estonia area. In the Ordovician igitalization helps to fix objec- period, continental seas and widespread deposi- tively and exactly the stone tion of carbonate sediments had a greater ex- texture and sedimentation tent in this period. The marine flora and fauna peculiarities; it can help to changed markedly in the course of the Ordovi- developD and document geological data and it cian period. Several major taxonomic groups can be also used at digital libraries of core (trilobites, bryozoans, echinoderms, brachio- data’s for any research. The main advantage of pods, ostracodes, chitinozoans and others) the herein used dry scanning technique its low – appeared or became common. In this respect, cost, simplicity and accessibility for everyone the Ordovician is one of the most interesting (student, geology hobbyist or researcher). A periods in the history of marine faunas, and detailed methodological description will be Estonia is among the areas in the world where given below. this fauna is well preserved and studied At the moment such sedimentary rocks as (Raukas, Teedumäe, 1997). oil shale, limestone and dolostone are mined in Oil shale resources in Estonia are notable Estonia. All of them are actively used in the (Ots, 2007). There are two oil shale types that production of different aggregates. Usually the can be found in this paper, which are wide- rock layers contain also other additional materi- spread in Estonia – dark-brown Dictyonema als, as a result, raw material quality and consti- Argillite (claystone) and light-brown oil shale tution vary from place to place in Estonia and (sedimentary Kukersite rock). Both of them the neighbouring Baltic states. belong to the Ordovician period, but light- Such geological periods as Quaternary, brown oil shale is the main type in Estonia and Devonian, Silurian, Ordovician, Cambrian, it belongs to the basal Upper Ordovician Ediacaran and Precambrian basement are formation. Oil shale beds have a stratified Содержимое этой работы может использоваться в соответствии с условиями лицензии Creative Commons Attribution 4.0. Любое дальнейшее распространение этой работы должно содержать указание на автора (ов) и название работы, цитирование в журнале и DOI. Общая и региональная геология 5 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 structure with mineral interbeds (Ots, 2007). enhancing the clarity of boundaries and con- There are fifty oil shale layers in total in North- trast. Unfortunately, it is quite inconvenient and ern Estonia. The lowest layers of the stage are unhandy, but it is considered in this paper as the most interesting from a mining viewpoint. well for methods comparison. Thin limestone interlayers separate this: pink, Such scanning results can be probably white and blue limestone or its macerals (Väli, achieved with professional digital photography Valgma, Reinsalu, 2008). equipment as well, but it involves multiple data Limestone and dolostone have been used in transfers (Mill, 2017), which inevitably causes the field of construction for thousands of years. certain distortion and inaccuracy at the quality The use of limestone as a decorative material is of the images; it is an expensive (Doehne, decreasing nowadays; modern Estonian Pinchin, 2008) and a labour-consuming process. architecture is focused on concrete, steel and The principal disadvantages of professional glass (Rähni, 2007). Polished or cut limestone, photography are the cost of all the necessary dolostone also, looks very elegant and it can be devices-instrumentations as the camera body, used as decorative stone by civil engineers and lenses and horizontal system tripod, complex architects, designers as well as interior decora- and sophisticated data storage as well as diffi- tors (Fig. 1). culties in archiving and analysing processes. As Nowadays good aggregate quality and raw a result, photographing cannot displace scan- material quality are required in all industry ning in this case and is not considered in this fields. For this purpose, representative core paper. Such equipment is justified in other re- samples of all previously described rocks of the searches when actions are needed immediately Ordovician period were used in the scanning at the field areas, which are new to the science, process as examples. Samples were studied in and waiting to be studied in fresh, untouched detail to introduce the easiest and the and natural conditions (Shu, Zi Bing, Wei- cheapest scanning technology and monitoring huen, Huang, Bo, Maciejewski, Fang, 2019). system for prospective data examples that can In this digitalization research, different be used by everyone at further investigations. types of rocks and layers of limestone and dolo- Next chapter introduce used scanning method- stone, also oil shale in some cases were used ology. (Fig. 1). The stratigraphical distribution, corre- Materials and Methods. The used scanning lation with global units and time slices of re- technique involves digital dry scanning of vised samples in the Baltic States and the Ordo- smooth rock surface and deals with the precise vician System are shown (Fig. 1.a) in Ordovi- and objective digital fixating of rock texture. cian stratigraphic chart with the successions of The limestone dry scanning method used in this main lithostratigraphical units of the Estonian study is a basic one; it was registered as Utility and Lithuanian shelves and Livonian Basin. Model No. EE00778U1 since 20.06.2008 until The numbers of the stages C1b, C1c, C2, D2, 20.06.2016 at the database of utility models in F2 were used for scanning. The formations and the Republic of Estonia to the extent specified members from the Livonian Basin and Lithua- in the Utility Models Act and was published at nian Shelf are shown in their stratigraphic suc- periodical official gazette of the Estonian Patent cession without exact correlation with the units Office (Estonian Patent Office, 2008). Gazette in the Estonian Shelf. Abbreviations used in the publication including the original texts and chart: S, Silurian; TREM., Tremadocian; Rh, translations, data in the register and notifica- Rhuddanian; Lw., Lower; Md., Middle; Up., tions published and has legal status (Estonian Upper; HUNNEB., Hunnebergian; BILLIN., Patent Office, 2008). Billingen; LASN., Lasnamägi; Vasal., Vasa- There is another similar method of sample lemma Formation. (Hints, Harperb, scanning. The method of direct scanning of Paškevičiusc, 2018). smooth rock surfaces with wet processing is The main results of this work were the well known nowadays: for the inspection of the improvement of scanning methods and digital rock’s structure and its microstructural details processing of cut and polished strips of drill the rock surface is first made wet to gain the cores that can be used for detailed core effect of smoothness of a polished surface, libraries, using simple office scanners. The

Общая и региональная геология 6 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020

Fig. 1a. Stratigraphic chart with correlation of regionaal and global units with time slices for Ordovician period (Hints, Harperb, Paškevičiusc, 2018) most important is that with informative scanned Each file name consists of the drill core number photographical data, it is easy to demonstrate or name and depth (for example PA45_16_37) the difference between each rock type and its which are nonrecurring throughout all drill core formations, to identify structural defect orienta- depths and thus cannot be duplicated. It is very tions, adequately assess strength as rock quality important to use colour images as this helps to designation (RQD) index, etc. To carnalize, avoid mistakes in the geological characteriza- measuring the surface of products using thin tions of samples and cross-section composition. strips is important nowadays in different coun- A millimetre scale was introduced to every tries (Chu, Chen, 2017). image to describe the sample’s size, its The main problems in the scanning process formation reference with number, depth and are caused by heavy stone pieces, lose quartz discontinuity surfaces as shown in the example sand or stone dust that impair image quality. To (Fig. 2). It is necessary to mention that such avoid these, the fine film can be used in every structural details as pyritic discontinuity surfac- scanning process. For this research, all scanned es, caverns, detritus or Kukersite content can images were saved and rigorously numbered. easily be presented by adding highlights to the Общая и региональная геология 7 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 image. It enables a much better interpretation The Preferred Implementation. The Utility and identification of important geological Model applied a method of precise digital details. Already used samples were placed back fixation of the varied inner rock patterns as a into drill core wooden boxes with 1 m length low-cost monitoring system. Scanning is done (Fig. 3). For easy scanning, samples were cut by placing a dry rock piece after its smooth into halves or even into strips. The strips were surface has been cleaned on to the holder of the dust free or polished; cleaning was done with a scanner and covered with transparent plastic wide brush or by brushing with water for purity film so that in case of direct contact the rock (Fig. 3). Detailed samples preparations are does not damage the scanning glass surface. described below in the Preferred Implementa- The scanning plate is placed on a pre-prepared tion chapter. rock surface and scanning is performed.

Fig. 1. Scanned images of limestone and dolostone rocks’ cross-sections: A – Lasnamäe limestone stage (Darriwilian international stage) parallel cross-section with double unconformity surfaces; B – Vasalemma stage parallel cross- section (Katian 5c time slice by IGCP 410 Time Scale); C – dolostone named Orgita; D – parallel cross-section of limestone named Ungru; E – layer of dolostone named Kaarma; F – Vasalemma limestone (Katian 5c time slice by IGCP 410 Time Scale); G – Lasnamäe limestone (Darriwilian part of 4c time sliceinternational stage); H, I – Sulu drill core base layers of dolostone named Orgita

Fig. 2. Signs of sample identification example at the Fig. 3. Cleaning and preparing strips of limestone image of limestone with depths, pyrite discontinuity surfaces, numeration of layers, and names with basic samples from Lipametsa location scale time and minimal cycle time. (Rähni, 2007) Общая и региональная геология 8 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 A 0,5...3 cm thick plate was cut using important that all parameters must be kept. In Husqvarna Construction Product Polishing case of adjusting the colour, the same principle machine TS600M for extra-large samples and as in changing the contrast applies. TS2301 for small ones out from limestone drill Image contrast is determined visually and it core. The surface of the sample was burnished is adjusted until the dominating grey shade of and polished firstly using a polishing machine the limestone sample becomes less dominant with waterproof silicon carbide paper P#80 and and brings out true colours, which can be seen after that polished with P#120. Only smooth by the naked eye. It brings out true structure surface shows a specific character of the rock’s details of the rock unconformity or burrows, the and its inner structure. The coarse surface does orientation of detritus, the content of oil shale, not reveal the inner structure, only the nature of etc. After adjusting the scanned surface’s the relief. Cutting time depends on sample size; contrast and colour, geological symbols, created usually it takes approximately 15 minutes to cut with photo editing and the scale are added to one thick plate. the scan. The scale was developed as follows: a For direct surface scanning, the absolute ruler with the same dot density and with photo prerequisite is the smoothness of the surface editing programme a millimetre scale of a ruler that in case of all dense rocks is achieved with was drawn separately. This scale was added to polishing. Dolomitized limestone is finely po- each column in full. After photo adding and rous and usually difficult to polish, in which adding symbols, the images can be transferred case fine grade burnishing is sufficient in A4 format on paper and printed out in colour. (Estonian Patent Office, 2008). Recommended file format for storing the Then the rock piece, dried after the clean- finished scans produced from originals is ing, the smooth surface is placed on the scanner popular JPEG with sRGB and Adobe RGB holder (for example compact flatbed HP Scanjet colour profiles (no capacious TIFF or RAW), 4600 with movable module) and covered with because it is the most common format for transparent plastic film, so that in case of direct storing and transmitting photos worldwide and contact the rock does not damage the glass sur- can be embedded in other file types. face of the scanner. The scanning glass plate is In the scanning process, maximum dots per placed onto the pre-prepared rock surface and inch value should be chosen to achieve the best digital scanning is performed. The scanner is picture quality. The more dots are used the adjusted as follows: dot density at least 600 dpi more the image can be zoomed and the (dots per inch). Since long and heavy limestone structure of the sample can be studied. Minimal cutter strips cannot be placed on the scanner all zooming is three times. at once, they have to be scanned in parts; each Wet Methodology Possibilities. Another part is saved as a separate file. Then several already used technology is wet scanning. Using separately scanned parts are combined into a wet stone for scanning immediately after whole with a photo common graphics-editing cleaning brings out important details and bright programme such as Adobe Photoshop, Corel colours. If it is tedious to manage wet stones the PHOTO-PAINT, Paintshop Pro or some free same effects can be achieved using graphics software like GIMP (https://www.gimp.org). As editor (contrast change). Improved scanned a result of which the necessary length of the images of construction limestone drill core scanned image is reached and photo colour edit- strips with pyritic discontinuity surfaces from ing can be done on the scanned rock image. limestone formation look vivid and the dulled Contrast can be adjusted only in two ways, images are not improved, not polished, but either by automatically or manually changing scanned (Fig. 4). As a result, distinctness is the programme, but when adjusting contrast, it better in the improved images and this enables is important to remember that all images (which to interpret the textures better. For structure are in separate files) need the same characteris- investigation, simple image enlargement can be tics in order to maintain the same contrast used. throughout the drill core and visual comparison Scanned Samples and Interpretation of with the samples is needed as well. How con- the Results. Studies of Ordovician rocks and trast is adjusted is not important, however, it is fossils in Estonia started long time ago in the

Общая и региональная геология 9 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 19th century. As a result most detailed regional Drill Core Samples of Middle Ordovician timescales are presented exactly in Estonia Systems. Ubja borehole (ID 211, No F156. x: (Fig. 1a) and neighbouring areas, also world- 6587973; y: 636736; by L-EST 97 system) wide but buy global units (Nõlvak, Hints, located in Lääne-Viru County, in north- Männik, 2006).The Ordovician Period was eastern Estonia was firstly described at 1973 described by a high global sea level and shallow (Internet 1). Now here it is well preserved, in seas spread over areas of the continents. All this cross-section marl and limestone for- known continents were situated in the southern mations can be seen, creatures mixed warp and part and the northern one was mostly one big as a result bioturbation occurred. All Kiviõli ocean. The majority of the multi-cellular member (CIc-CIIV'K | O3vvK) and other layers systems were bound to marine environments, although plants began to populate the land which are located at the depth of 7,2...15,0 m about halfway through the period. Thus, marine belong to the Uhaku stage (Darriwilian time sedimentary rocks form the main archive from slice 4c by IGCP 410 Time Scale) (Fig. 6). It which we extract information about this time. can be seen that some Kukersite bedding for- (Lindskog, 2017). The Middle Ordovician and mations are mixed with limestone ones. These the Ordovician-Silurian boundary intervals are layers of Kukersite (Fig. 6, part I) contain more described below using scanned images of the clay and fewer organics than usual Kukersite strips, taking into account the conditions of formations, the colours are lighter, layers are Estonia, a part of the paleocontinent Baltica, thinner, discontinuity surfaces are less distinct Baltoscandian region. In this paper, only three (Fig. 6, part II-IV). Clay content in Kukersite is boreholes were described in detail, their l almost the same as in marl. Kukersite layers are ocations can be found in Fig. 5. usually covered with Eurypterus-dolostone of Silur, thus the lower layer is regressive and less contrasted. (Einasto, Rähni, Allev, 2006) Ülemiste No 2 borehole (ID: 1512) is locat-

ed near Tallinn city, it was firstly described in

1966 (Internet 2). Its cross-section is the most representative one of Uhaku stage (Darriwilian

4c by IGCP 410 Time Slice) as Kõrgekallas formation and partly Väo formation (4c by

IGCP 410 Time Slice). Layer-by-layer dissec- tions of this drill core are important for interna-

tional stratigraphic scaling as a basis of Ordovi- Fig. 4. Improved (A) by digital tools and non-improved cian margin with its series and formed layers by (B) limestone boring-core sample images of limestone bio-stratigraphic units of limestone. Estonia formation where pyrite discontinuity surfaces can be seen in Darriwilian time slice 4c by IGCP 410 Time Scale. was sculptured by the glacier, as a result, a lot (Rähni, 2007) of limestone upper layers are not demonstrated at any drill core, besides Ülemiste drill core, which is the only one (Einasto, Rähni, 2006a). Discontinuity surfaces are significant. They are Ülemiste Ubja indicating sedimentation setting at the surface Seli-Reinu of the shallow northern sea and sea bottom that Koigi was influenced by different setting factors: erosion by sediment grains due to water movements, water solvent impact and

karstification, etc. As a result, the Kõrgekallas formation and partly Väo formation (4c by IGCP 410 Time Slice) contain six obvious pyritic discontinuity Fig. 5. Described boring holes’ locations on the map of surfaces with rounded cavities. These Estonia, where the distribution of bedrock valleys can be seen as well. Composed using Geoscience Collections of formations can be easily recognized in other Estonia. (Geoscience Collections, 2019) drill cores just by discontinuity surfaces. It can

Общая и региональная геология 10 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 be seen in the digital cross-section (Fig. 7) that 25,67 m (Fig. 7). Typical fossils (Gymngraptus pyritic discontinuity surfaces partly contain bedrock linnarssoni) were first found between these disconti- particles at the depths of 25,80...25,78 m and nuity surfaces in 1970 (Einasto, Rähni, Piht, 2006b). 25,76...25,70 m, and discontinuity is marked at

Fig. 6. Ubja drill core digital cross-section of Kiviõli member (CIc-CIIV'K | O3vvK) and Kõrgekallas formation (part of 4c by IGCP 410 Time Slice) dissection where deep karst formations are shown belongs to the Middle Ordovician system. (Einasto, Rähni, 2006a) Общая и региональная геология 11 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020

Fig. 7. The digital cross-section of Kõrgekallas formation (part of 4c by IGCP 410 Time Slice) dissections belongs to a more investigated stratigraphic gap of Middle Ordovician systems where coarse synchronically margins can be seen (Einasto, Rähni, Piht, 2006b)

The most vivid changes can be seen at the 19,8...19,9 m (Fig. 8). The most oil shale rich depth of 25,8 m where pyritic discontinuity sur- layers are A and B, thin layers are A’ (less than faces with deep curve cavities are demonstrated. 1 cm) and D with fragmentary kukersite organic The exposed layer with dark, contrasting, black component (Gloeocapsomorpha), C and F l patchy discontinuity surfaces at 25,7...25,88 m ayers are with fragmentary Kukersite organic is the famous thin coat between clay layers (no limestone lenses. It can be seen that bedrock 15 at Fig. 7) which was used as a stair rock. In and caprock have a relatively familiar combina- addition, neighbouring layers beds (no 14 and tion and construction. The variety of many 16 in Fig. 7) have interesting patterns and good Infauna vital functions are conspicuous in all rock quality with high resistance and no marl. layers. (Einasto, Rähni, Piht, 2006b) An important difference between the layers Oil shale digital cross-section of formations is the construction and thickness of the can be seen in the Ülemiste drill core located limestone. A and B blue-grey clayey limestone near Tallinn city where the Kukruse regional formation is only 2 cm thick and demonstrates stage (Sandbian international stage (Vinn, detrition impressions on both sides, fragmen- Ernst, Toom, Isakar, 2018)) Kiviõli member’s tary Kukersite organic limestone located lower part is clearly exposed. The most im- between D and E is up to 10 cm thick (also portant indicators in this cross-section are the named as pink layer) with weak pyritic symmetrical parts of interlayer at the depth of discontinuity surfaces at the centre and the top.

Общая и региональная геология 12 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 A very representational asymmetry is interlayer This part of the rock has the most beautiful dec- bottom at 19,9 m with clear irregular cavities orative structure pattern and is used for interior and bright lime material C-layer upper side. decorations (Einasto, Rähni, Allev, 2006).

Fig. 8. Digital cross-section of kukersite layers in Ülemiste drill core, where Kukruse stage (5a by IGCP 410 Time Slice, Sandbian international stage (Vinn, Ernst, Toom, Isakar, 2018) lower part is presented (Einasto, Rähni, 2006c)

Drill Core Samples of Ordovician-Silurian well-preserved non-dolomitized limestone with Systems. The boundary between the Ordovician corals, crinoids and other fossils at Roä member and Silurian systems was established at the is very rare. The Koigi member is missing in level close to the lowest occurrences of Varbola formations (G1-2V | S1vr) at Akidograptus Ascensus in the Dob’s Linn 11,2...12,9 m depth. (Einasto et al., 2007). section and ratified in 1984 by IUGS (Holland, Conclusions and Discussion. During the 1985). This boundary marks the termination of last ten years, much international work was a complicated episode in the Ordovician written about establishing a system of globally history, the time of the great End-Ordovician recognizable series and stages in the Ordovician glaciation. The glaciation caused mass extinc- Period (Chen et al., 2009). The absolute tion, several sea-level changes, the formation of (numeric) time scale for the Ordovician is still gaps and lithology characteristic in the sections. poorly resolved. This presents problems for the Definitely, for better understanding these understanding of the timing, events and important events, a reliable stratigraphical processes during the time interval (Lindskog, framework is of great help. Latvian and Estoni- 2017). Different scanning is used at geological an sections can provide useful examples, investigations to archive images of the despite the fact that true graptoloids do not oc- boreholes and drill cores (Thermann et al., cur in this interval. (Kaljo et al., 2008). 2016). Several drill cores with Ordovician-Silurian This research presents an overview of boundary beds, one of them is the Seli-Koigi already digitalized continuous cross-sections of Reinu drill core drilled out in the course of open limestone, dolostone and oil shale layers. These -pit mining research works near area in cross-section samples are rare and describe how Raplamaa province (Fig. 5). Until then those scanning results can be interpreted in a geologi- layers had never been uncovered in the Estonian cal context, and allows selecting between region. In these samples, the non-dolomitized different textures of rock formation, where layers are the most interesting: Porkuni stage every sample has its own special pattern and Ärina formation (part of 4c of Hirnantian by paragon. Proper digital core images offer the IGCP 410 Time Slice) and bedrock with highest resolution realization of core properties caprock. This cross-section of Ordovician- available to scientific investigators (Wilkens et Silurian margin layers is the most northward in al. 2009). Estonia which means that this cross-section is This simple methodology was developed in also the nearest to the shallow seacoast where the geological laboratory and the main idea was bright yellow-grey Vohilaiu member (no 37 at to simplify the scanning process of polished Fig. 1.a) of pure limestone dominate the organi- limestone cores and to digitalize and archive a cally rich dark brown Siuge member (no 38 at lot of geological samples. The primary Fig. 1.a) of limestone strata below (Fig. 9). The advantages of this methodology are its low cost, Общая и региональная геология 13 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 simplicity and moderate data capacities require- ing scientific issues and new possibilities for ments for collected images. Digitalized data can limestone extraction or excavations. Detailed be useful for geologists, researchers, also for methodology were described above. resource mining developers, means for resolv-

Fig. 9. Ordovician-Silurian margin layers of the Seli-Koigi Reinu drill core digitalized sample. stage (Rhuddanian by Global Standard Stage, Silurian series) Varbola formation deepness 11,2...12,9 m is weakly blue-grey clayey limestone with Stromatopora and corals where thin marl layers were washed out during drillings and stages margins were damaged at drilling works. Porkuni stage (6c IGCP 410 Time Slice) Ärina Vohiainu II member, 12,9...13,5 m depth, illustrates pure sorted-laminated limestone with unconformity surface at bottom margin. Siuge member are demonstrated at 13,5...14,3 m as brown massive clayey limestone with crusted Stromatopora, includes pyrites unconformity surfaces at the bottom margin. Vohilaiu I (6c IGCP 410 Time Slice) member are shown at 14,3...15,15 m as bright yellow and brownish-grey pure sorted-laminated limestone. Röa member (6c IGCP 410 Time Slice) are 15,15...15,9 m brownish-grey with lots of gross Echinodermata joints, at the bottom margin deep pyrite curve cavities can be seen ~25 cm unconformity surface which is filled with marl and indicates karstification. stage (6a...6b IGCP 410 Time Slice) Kabala Member presented at 15,9...16,6 m, gray well sorted homogeneous limestone with unconformity surface cavities, after 16,3 m presented greenish-grey lime marl and clayey limestone varying; bottom margin is sharp-edged. Adila formation (6b IGCP 410 Time Slice) shown at 16,6...17,7 m has beige-grey clayey limestone with lime marl, at 17,5 m and 17,65 m deepness with strongly putrid edges – broken at storm and rounded unconformity surfaces; at 16,15...16,25 m and 16,60…16,70 m bright brown adjoining rocks, which are swelled due to ground-water rabbets. (Einasto, Rähni, 2007) A long time ago, drill core images were needs more improvements and subject-aimed digitalized by taking a roll films photography, use in the international field of aggregate in analogue format and then printed; nowadays research. The main idea of this work is to create scanning seems to be the right decision. The for researchers and other users a drill core scanning and digital processing used in geology image archive, a database as a digital library.

Общая и региональная геология 14 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 It is important to preserve rock samples 8. Einasto, R., Rähni, A. Ordoviitsiumi- material with drill core continuous cutting Siluri piirkihid Seli-Koigi Reinu sections and archive scanned information for puursüdamikus. Keskonnatehnika. 20007. (2). future research. Scanned images can be used for Рp. 63-65. further lithological investigation in any Baltic 9. Hints, L., Harperb, D.A.T., Paškevičiusc, country, to identify reveal discontinuities at any JDiversity and biostratigraphic utility of Ordo- further researches or reports. Emphasising the vician brachiopods in the East Baltic. Estonian value of the results, research should be contin- Journal of Earth Sciences. 2018. https:// ued and more work needs to be done on samples doi.org/10.3176/earth.2018.14 scanning. 10. Kaljo, D., Einasto, R., Hints, L. Stop Acknowledgements. The authors wish to B2: Ordovician-Silurian boundary in Estonia: acknowledge linguistic editor Klea Vaher and localities at Porkuni and Neitla. The Seventh some anonymous reviewers for constructive, Baltic Stratigraphical Conference, Estonia. thought-provoking comments and suggestions Abstracts & Field Guide. Tallinn: Geological that have improved this manuscript. Samples Society of Estonia, 2008. Рp. 100-104. cutting, polishing and scanning experiments 11. Lindskog, A. Early-Middle Ordovician with samples storage were held at TTK Univer- biotic and sedimentary dynamics in the sity of Applied Sciences, laboratories of Civil Baltoscandian paleobasin. Lithosphere and Bio- Engineering Institute. sphere Science. Department of Geology. 2017. 12. Mill, T. Application of terrestrial laser References scanning technology for engineering structure 1. Chen, X., Bergström, S.M., Zhang, Y-D., surveys. Tallinn: TTÜ Press, 2017. Рp. 11, 13. Fan, J-X. The base of the Middle Ordovician in 13. Nõlvak, J., Hints, O., Männik, P. Ordo- China with special reference to the succession at vician timescale in Estonia: recent develop- Hengtang near Jiangshan, Zhejiang Province, ments. Proceedings of the Estonian Acade- Southern China. Lethaia. 2009. (42). my of Sciences. 2006. 55(2). Рр. 95-108. Рp. 218-231. 14. Ots, A. Estonian Oil Shale properties 2. Chu, C.-L., Chen, H.-C. Development of and utilization in power plants. Energetika. a surface scanning touch probe for micro- 2007. 53(2). Рp. 8-18. CMM. International Conference on Applied 15. Raukas, A., Teedumäe, A. Geology and System Innovation (ICASI). 2017. Mineral Resources of Estonia. Estonian Acade- DOI: 10.1109/ICASI.2017.7988471. my Publishers, Tallinn, 1997. 3. Doehne, E., Pinchin, S. Time-lapse Mac- 16. Rähni, A. Estonian Limestone as a ro-imaging in the Field: monitoring rapid flak- Building Material on Example of Digital ing of Magnesian Limestone. Proceedings of the Processing. TTK University of Applied Sci- 11th International Congress on Deterioration ence. 2007. and Conservation of Stone. Torun, 2008. 17. Shu, L., Zi Bing, X., Weihuen, C., 4. Einasto, R., Rähni, A., Allev, E. Põlev- Huang, Y., Bo, P., Maciejewski, S., Fang W. kivi tootsa kihindi digiläbilõige Tallinna Five new species of the genus Primulina lähistelt. Keskonnatehnika. 2006. (2). Рp. 51-52. (Gesneriaceae) from Limestone Areas of 5. Einasto, R., Rähni, A. Kõrgekalda ki- Guangxi Zhuangzu Autonomous Region, Chi- histu digiläbilõige Ülemiste puursüdamikus. na. PhytoKeys. 2019. doi: 10.3897/ Keskonnatehnika. 2006. (4). Рp. 43-45. phytokeys.127.35445 6. Einasto, R., Rähni, A., Piht, H. Katkes- 18. Thermann, K., Stabel, B. Investigations, tuspinnad Väo ja Kõrgekalda kihistu piirkih- in-situ tests and stress measurement for the tides (Ülemiste puursüdamik). Keskonnatehni- powerhouse complex of the Lagobianco ka. 2006. (2). Рp. 52. pumped storage project. Rock Mechanics and 7. Einasto, R., Rähni, A. Kiviõli kihistiku ja Rock Engineering: From the Past to the Future. Kõrgekalda kihistu digiläbilõige Ubja 2016. puursüdamikus. Keskonnatehnika. 2006. (5). 19. Vinn, O., Ernst, A., Toom, U., Isakar, Рp. 43-48. M. Cryptic encrusting fauna inside invertebrate fossils from the Ordovician of Estonia. Annales

Общая и региональная геология 15 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 Societatis Geologorum Poloniae. 2018. doi: J.E.T., Kanamatsu, T., Sato, T., Stein, R., Al- 10.14241/asgp.2018.008, https:// varez Zarikian, C.A., Malone, M.J., and the www.researchgate.net/publication/328912700 Expedition 303/306 Scientists Proceedings of 20. Väli, E., Valgma, I., Reinsalu, E. Usage the Integrated Ocean Drilling Program. 2009. of Estonian oil shale. Oil Shale. (2008). 25(2S). 22. https://geoportaal.maaamet.ee/ Рp. 101-114. index.php? 21. Wilkens, R.H., Niklis, N., Frazer, M. &action=viewPA&page_id=382&pa_id=4971. Data report: digital core images as data: an 23. Geoscience Collections of Estonia Web example from IODP Expedition 303; Channell, Server http://geokogud.info/locality/1512.

Contacts: Julija Šommet, [email protected] Rein Einasto, [email protected]

© Šommet, J., Einasto, R., 2020

Šommet, J., Einasto, R., 2020. A Geological Overview of Digitalized Rock Drill Core Samples of Ordovician Period in Estonia. Vector of Geosciences. 3(2). Pp. 5-16. DOI: 10.24411/2619- 0761-2020-10013.

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